'\"
'\" Generated from file 'xsxp\&.man' by tcllib/doctools with format 'nroff'
'\" 2006 Darren New\&. All Rights Reserved\&.
'\"
.TH "xsxp" n 1\&.0 tcllib "Amazon S3 Web Service Utilities"
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.SH NAME
xsxp \- eXtremely Simple Xml Parser
.SH SYNOPSIS
package require \fBTcl  8\&.4\fR
.sp
package require \fBxsxp  1\fR
.sp
package require \fBxml \fR
.sp
\fBxsxp::parse\fR \fIxml\fR
.sp
\fBxsxp::fetch\fR \fIpxml\fR \fIpath\fR ?\fIpart\fR?
.sp
\fBxsxp::fetchall\fR \fIpxml_list\fR \fIpath\fR ?\fIpart\fR?
.sp
\fBxsxp::only\fR \fIpxml\fR \fItagname\fR
.sp
\fBxsxp::prettyprint\fR \fIpxml\fR ?\fIchan\fR?
.sp
.BE
.SH DESCRIPTION
This package provides a simple interface to parse XML into a pure-value list\&.
It also provides accessor routines to pull out specific subtags,
not unlike DOM access\&.
This package was written for and is used by Darren New's Amazon S3 access package\&.
.PP
This is pretty lame, but I needed something like this for S3,
and at the time, TclDOM would not work with the new 8\&.5 Tcl
due to version number problems\&.
.PP
In addition, this is a pure-value implementation\&. There is no
garbage to clean up in the event of a thrown error, for example\&.
This simplifies the code for sufficiently small XML documents,
which is what Amazon's S3 guarantees\&.
.PP
Copyright 2006 Darren New\&. All Rights Reserved\&.
NO WARRANTIES OF ANY TYPE ARE PROVIDED\&.
COPYING OR USE INDEMNIFIES THE AUTHOR IN ALL WAYS\&.
This software is licensed under essentially the same
terms as Tcl\&. See LICENSE\&.txt for the terms\&.
.SH COMMANDS
The package implements five rather simple procedures\&.
One parses, one is for debugging, and the rest pull various
parts of the parsed document out for processing\&.
.TP
\fBxsxp::parse\fR \fIxml\fR
This parses an XML document (using the standard xml tcllib module in a SAX sort of way) and builds a data structure which it returns if the parsing succeeded\&. The return value is referred to herein as a "pxml", or "parsed xml"\&. The list consists of two or more elements:
.RS
.IP \(bu
The first element is the name of the tag\&.
.IP \(bu
The second element is an array-get formatted list of key/value pairs\&. The keys are attribute names and the values are attribute values\&. This is an empty list if there are no attributes on the tag\&.
.IP \(bu
The third through end elements are the children of the node, if any\&. Each child is, recursively, a pxml\&.
.IP \(bu
Note that if the zero'th element, i\&.e\&. the tag name, is "%PCDATA", then
the attributes will be empty and the third element will be the text of the element\&. In addition, if an element's contents consists only of PCDATA, it will have only one child, and all the PCDATA will be concatenated\&. In other words,
this parser works poorly for XML with elements that contain both child tags and PCDATA\&.  Since Amazon S3 does not do this (and for that matter most
uses of XML where XML is a poor choice don't do this), this is probably
not a serious limitation\&.
.RE
.sp
.TP
\fBxsxp::fetch\fR \fIpxml\fR \fIpath\fR ?\fIpart\fR?
\fIpxml\fR is a parsed XML, as returned from xsxp::parse\&.
\fIpath\fR is a list of element tag names\&. Each element is the name
of a child to look up, optionally followed by a
hash ("#") and a string of digits\&. An empty list or an initial empty element
selects \fIpxml\fR\&. If no hash sign is present, the behavior is as if "#0"
had been appended to that element\&. (In addition to a list, slashes can separate subparts where convenient\&.)
.sp
An element of \fIpath\fR scans the children at the indicated level
for the n'th instance of a child whose tag matches the part of the
element before the hash sign\&. If an element is simply "#"  followed
by digits, that indexed child is selected, regardless of the tags
in the children\&. Hence, an element of "#3" will always select
the fourth child of the node under consideration\&.
.sp
\fIpart\fR defaults to "%ALL"\&. It can be one of the following case-sensitive terms:
.RS
.TP
%ALL
returns the entire selected element\&.
.TP
%TAGNAME
returns lindex 0 of the selected element\&.
.TP
%ATTRIBUTES
returns index 1 of the selected element\&.
.TP
%CHILDREN
returns lrange 2 through end of the selected element,
resulting in a list of elements being returned\&.
.TP
%PCDATA
returns a concatenation of all the bodies of
direct children of this node whose tag is %PCDATA\&.
It throws an error if no such children are found\&. That
is, part=%PCDATA means return the textual content found
in that node but not its children nodes\&.
.TP
%PCDATA?
is like %PCDATA, but returns an empty string if
no PCDATA is found\&.
.RE
.sp
For example, to fetch the first bold text from the fifth paragraph of the body of your HTML file,
.CS

xsxp::fetch $pxml {body p#4 b} %PCDATA
.CE
.sp
.TP
\fBxsxp::fetchall\fR \fIpxml_list\fR \fIpath\fR ?\fIpart\fR?
This iterates over each PXML in \fIpxml_list\fR (which must be a list
of pxmls) selecting the indicated path from it, building a new list
with the selected data, and returning that new list\&.
.sp
For example, \fIpxml_list\fR might be
the %CHILDREN of a particular element, and the \fIpath\fR and \fIpart\fR
might select from each child a sub-element in which we're interested\&.
.sp
.TP
\fBxsxp::only\fR \fIpxml\fR \fItagname\fR
This iterates over the direct children of \fIpxml\fR and selects only
those with \fItagname\fR as their tag\&. Returns a list of matching
elements\&.
.sp
.TP
\fBxsxp::prettyprint\fR \fIpxml\fR ?\fIchan\fR?
This outputs to \fIchan\fR (default stdout) a pretty-printed
version of \fIpxml\fR\&.
.PP
.SH "BUGS, IDEAS, FEEDBACK"
This document, and the package it describes, will undoubtedly contain
bugs and other problems\&.
Please report such in the category \fIamazon-s3\fR of the
\fITcllib Trackers\fR [http://core\&.tcl\&.tk/tcllib/reportlist]\&.
Please also report any ideas for enhancements you may have for either
package and/or documentation\&.
.PP
When proposing code changes, please provide \fIunified diffs\fR,
i\&.e the output of \fBdiff -u\fR\&.
.PP
Note further that \fIattachments\fR are strongly preferred over
inlined patches\&. Attachments can be made by going to the \fBEdit\fR
form of the ticket immediately after its creation, and then using the
left-most button in the secondary navigation bar\&.
.SH KEYWORDS
dom, parser, xml
.SH CATEGORY
Text processing
.SH COPYRIGHT
.nf
2006 Darren New\&. All Rights Reserved\&.

.fi
